Heat-treated detergent compositions



United States Patent 3,248,331 HEAT-TREATED DETERGENT COMPOSI'IIUNS .laclr Thomas lnamorato, Flushing, N.Y., assignor to Colgate-Palmolive Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 1, 1960, Ser. No. 66,432 10 Claims. (M. 252-138) The present invention relates to a heat-treated, solidified detergent composition comprising a water-soluble higher alkyl aryl sulfate detergent and a Water-soluble polyvinyl alcohol soil-suspending agent which is normally stable to aging at an elevated temperature in an aqueous medium therewith prior to solidification of said mixture and to a process for preparing said composition, as hereinafter described and claimed.

It is known in the detergent art to prepare compositions containing an organic detergent and a soil-suspending or anti-redeposition agent which inhibits the deposition of soil onto the fabric during the washing operation. A large variety of chemical materials has been proposed as soil-suspending agents including natural and synthetic gums, cellulose derivatives such as carboxy-methylcellulose, protein materials, and various synthetic polymers including polyvinyl alcohol. The soil-suspending agent which has received wide acceptance in the art has been sodium carboxymethylcellulose.

The preparation of heat-treated detergent compositions in solid form is known in the art also. For example, an aqueous slurry of a detergent composition containing a suitable detergent may be heated and maintained at an elevated temperature for a desired time and then dried to form a solid product in particulate form such as granules, beads, flakes and the like.

The present invention relates to a heat-treated, solidified detergent composition comprising a water-soluble higher alkyl aryl sulfonate detergent and a minor proportion, e.g., 0.05 to by weight of water-soluble polyvinyl alcohol sufficient as a soil-suspending agent which is normally stable upon aging in an aqueous medium in combination with said detergent at an elevated temperature prior to solidfication of said mixture, said polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of to 30% by weight. A feature of the present invention relates to a heat-treated laundering composition in particulate form comprising about 5 to 50% by weight of water-soluble higher alkyl benzene sulfonate detergent, about 0 .05 to 5% each by weight of a mixture of water-soluble cellulosic soil-suspending agent and water-soluble polyvinyl alcohol having the indicated viscosity and acetate content, and the balance being primarily water-soluble inorganic salts, preferably with 10 to 80% by weight of alkaline inorganic builder salts.

in the preparation of heat-treated, solidified detergent compositions, it has been found that the type of polyvinyl alcohol employed as a soil-suspending agent is signiiicant. Such product may exhibit marked decreased soil-suspending power depending upon the type of polyvinyl alcohol present, compared to the effect of a mechanical mixture of the same ingredients. For example, the heating of an aqueous slurry and a particular grade of commercial polyvinyl alcohol in a crutcher for up to about one hour at an elevated temperature, e.g., 160 180 F., followed by spray-drying, results in a product having such reduced soil-suspending power. Further research has shown that this defect is due primarily to such factors as the nature of the polyvinyl alcohol in combination with said detergent in the aqueous slurry when it is subjected or aged at elevated temperatures prior to drying of the slurry to a solid composition.

The polyvinyl alcohol used should be sufficiently stable in the heated aqueous detergent slurry over the usual mixing and holding time intervals prior to drying so that there is no substantial decrease in the soil-suspending power of the final product when employed in washing baths. It has been found that water-soluble polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of about 10 to 30% by weight is satisfactory therein. The above reference to the viscosity refers to determinations made in a 4% aqueous solution at 20 C. Such material may be prepared in any suitable manner such as by control of the degree of polymerization and alcoholysis of the polyvinyl acetate to produce a product of the above characteristics. The above viscosity range corresponds to an approximate weight average degree of polymerization of about 35 to 100. The polyvinyl alcohol functions as an additive to the detergent composition to improve the soilsuspending power. It will be employed in minor proportion to said detergent therefore, and usually in an amount from about 0.05 to 5%, preferably 0.1 to 2%, by weight of total solids, and usually up to 1%.

The water-soluble higher alkyl aryl sulfonate detergents are known in the art and will usually have an average of about 8 to 15 carbon atoms in the alkyl group. It is preferred to use the higher alkylbenzene sulfonate detergent, though other similar detergents having a mono-nuclear aryl group, such as toluene, xylene or phenol may be used also. The higher alkyl substituent on the aromatic nucleus may be branched or straight chain in structure. Examples of branched-chain substituents are nonyl, dodecyl and pentad-ecyl groups derived from polymers of lower monoolefins including mixtures thereof, and examples of straight chain alkyl groups are decyl, keryl and the like, preferably with 12l5 carbons.

These sulfonated detergents are used preferably in the form of their alkali metal salts such as the sodium and potassium salt-s. Other water-soluble salts such as the nitrogen-containing salts may be used also, example being the ammonium, mono-, d-i-, and triethanolamine salts, and isopropanolamine salts of said detergents. They are employed in any suitable amount in the composition but will be in an amount greater than the amount of soil-suspending material, and usually at least about 5% by weight of total solids. In laundering compositions, the detergent content will be usually from about 5 to 50%, preferably 10 to 45% by weight.

If desired, suitable amounts of other detersive materials may be incorporated in the composition, such as suitable non-ionic and sul-fated organic detergents. Examples thereof are the normal and secondary higher alkyl sulfate detergents, particularly those having 8 to 15 carbons in the alkyl residue such as lauryl (or coconut fatty alcohol) sulfate, the higher alkyl ether sulfates, higher alkyl glyceryl ether sulfonates, higher alkyl phenol polyethylene oxide sulfates, polyoxyethylene e-thers of fatty alcohols, polyethylene oxide condensates with higher alkyl phenols such as nonyl and iso-octyl phenol condensed with 8 to 20 moles of ethylene oxide, preferably about 10, and polyethylene oxide condensates with hydrophobic polypropylene glycols.

There is present usually various amounts of watersoluble inorganic salts in the composition. Water-soluble neutral builder salts such as sodium sulfate may be present in admixture with the detergent since such sulfate salts are formed in the manufacture of the alkyl aryl sulfonate by certain commercial methods. Additional amounts of such inorganic sulfates may be added as desired. In compositions designed for laundering of heavily-soiled articles, it is preferred to add a substantial amount of water-soluble alkaline inorganic builder salts,

3. such as about to 80% by weight of total solids, preferably 20 to 60%. These salts are preferably the alkali metal polyphosphate salts which have the property of inhibiting precipitation of calcium and magnesium material in aqueous solution and of contributing to the heavy-duty performance of the detergent product. They may be considered as derived from orthophosphoric acid or the like by the removal of molecularly-bound water, though any suitable means of manufacture may be employed if desired. Such complex or molecularly dehydrated polyphosphate salts may be used in the form of the normal or completely neutralized salt, e.g., pentasodium tripolyphosphate, or partially neutralized salt, e.g., sodium acid tripolyphosphate. Other phosphate salts are pentapotassium tripolyphosphate, tetrasodium and tetrapotassium pyrophosphate, sodium tetraphos phate, sodium hexametaphosphate and the like including any desired mixtures thereof.

Other alkaline builder salts may be employed also such as the water-soluble alkali metal silicates. These silicates may be employed as the sole builder salt if desired or in combination with the polyphosphates. Suitable silicates are those having an alkali metal oxide to silica ratio within the range of about 1:1 to 1:4, and pref erably from about 1:2 to 1:3. Examples are sodium silicates having an Na O to SiO ratio of 1:2.35, 1:2.5, 1:3.2, 1:2.0, 1:1.6 and 1:1. Other materials are borax and sodium carbonate.

The preferred composition contains a hydrophobic colloidalcellulosic soil-suspending agent which is soluble or dispersible in water also. The joint use of the combination of the cellulosic compound and the polyvinyl alcohol is particularly effective for soil-suspension properties during the washing of a variety of fabrics, including both cotton and synthetic fibers such as nylon and Dacron and resin-treated cottons. The mixture is used preferably in a total amount of 0.1 to 2% by weight of the solids. It is preferred also to use the two agents in a ratio from about 20:1 to 1:20 by weight. The cellulosic compound is preferably the alkali metal salts of a carboxy lower alkyl cellulose having up to 3 carbons in the alkyl group such as the sodium and potassium salt of carboxymethylcellulose. Sodium carboxymethylcellulose and the like are available usually in the form of powders in various grades of purity and viscosity in so1ution. The commercial grades of sodium carboxymethylcellulose having a purity from about 60 to 100% on a dry basis and which are of low, medium or high viscosity may be employed. The degree of substitution of the carboxymethyl group per anhydroglucose unit in the cellulose molecule is variable, but is within the range from about 0.5 to 2, and usually up to about 1.25 substitution. It is preferred to employ carboxylated cellulose having about 0.5 to 0.9 substitution, and particularly about 0.5 to 0.7. Other salts are sodium carboxyethylcellulose, the cellulose sulfates and suitable lower alkyl and hydroxyalkyl ethers such as methyl-, ethyland hydroxyethylcellulose.

In the manufacture of the composition, there is formed an aqueous mixture such as a slurry of the ingredients in substantially homogeneous form. The preferred method comprises forming a fluid aqueous slurry of the organic detergent which flows or is pumped into a conventional soap crutcher or any other suitable mixing apparatus such as a ribbon blender. The other ingredients are then added in any suitable order and form. The polyvinyl alcohol is added usually as a fine white powder with stirring. The slurry should be sufliciently fiuid at the elevated temperatures to insure adequate mixing and formation of a uniform product.

The aqueous mixture is subjected to a heat-treatment at an elevated temperature such as within the range of about 100 to 200 F., and usually from about 120 to 180 F. The slurry is heated by external means or even by the exothermic heat of reaction of certain ingredients when added to the slurry depending upon the desired temperature. For example, the addition of hydratable inorganic salts such as the anhydrous forms of sodium tripolyphosphate and sodium pyrophosphate results in exothermic reactions as hydration occurs. The elevated temperature of the slurry aids in the mixing of the ingredients and in solubilization or hydration effects of specific ingredients in the slurry. The time interval of the mixing operation should be sufficient to insure adequate mixing which will he usually at least a few minutes, e.g., 5 minutes. In certain techniques known in the art, the aqueous mixture prior to drying is aged at the elevated temperature for a time sufiicient to insure adequate solubilization or hydration of certain ingredients. Such aging period may be for a number of hours, such as up to about 8 hours. In general, it is preferred to employ time intervals of less than three hours prior to heat-drying, and preferably less than one hour. It is understood that excessively high temperatures or unduly long aging periods will be avoided to prevent any possible decomposition and insure efiicient processing.

The solids content of the aqueous slurry is determined by the type of drying operation to be employed and will be usually within the range from about 20% to total solids. In the manufacture of heat-dried products involving vaporization of the water, the solids content will be usually within the range of about 40 to 65% by weight, the remainder being substantially free water content. It is usually maintained at a temperature from about to F. The slurry may be subjected to any suitable heat-drying operation and converted to particle form. For example, the material from the crutcher or mixing vessel may be sent into a drop tank from where it may be added to a drying zone such as a spray tower. This mixture may be subjected to the conventional spraydrying, roll-drying or drum-drying operations utilizing temperatures above about 212 F. to produce the detergent composition in particulate form. As a result, the detergent composition is obtained in the form of heatdried homogeneous particles, such as beads, granules, flakes, chips, powders or the like as desired.

It is preferred to spray-dry the aqueous slurry whereby it is atomized or forced through spray nozzles into towers, with the small liquid particles becoming solidified and drying as they contact or fall through a stream or vortex of heated air or products of combustion. The composition is produced thereby in the form of hollow thin-walled spheres or beads, characterized by excellent solubility in water and uniformity of particles, having a small residual moisture content usually of about 3 to 15% by weight.

Alternatively, the aqueous slurry may be solidified or dried by other suitable methods which do not involve vaporization of the water content. The slurry can contain sufiicient water for adequate mixing and hydration of the hydratable inorganic salts to the extent desired without any significant excess water content so that a dry and solidified mass is formed upon suitable aging at room temperature or slightly elevated temperatures such as up to about 120 F. The solidified mass may be granulated to form particles or granules of desired size.

Various other materials may be added in known manner manner to the aqueous slurry or after solidification. Examples thereof are higher fatty acid amides such as coconut or lauric monoethanolamide, isopropanolamide and diethanolamide; fatty alcohols such as lauryl alcohol, coconut fatty alcohols or cetyl alcohol; lower alkyl aryl sulfonates such as xylene or toluene sulfonates; coloring agents, corrosion inhibiting agents, bleaching agents, foam stabilizers or inhibitors as desired, detergency improving additives, and the like.

It is to be understood that the following examples are further illustrative of the present invention and that they are not intended to limit the scope thereof. All proportions are by weight unless otherwise specified.

Example I A heat-treated detergent composition in particulate form is prepared according to the following approximate formulation:

The product is prepared by adding to a crutcher a 60% solids aqueous solution of the sulfonate detergent admixed with some sodium sulfate formed in its manufacture. The alkyl group of the detergent is derived from a mixture containing propylene tetrarner and pentamer corresponding on the average to ya tridecyl group. There is added the remainder of the sodium sulfate and the carboxymethylcellulose powder which is a commercial grade of about 67% purity. The polyvinyl alcohol having a viscosity of 2.34 centipoises and 22.3% polyvinyl acetate is added with stirring at a temperature of about 120 F. to form a uniform slurry. The sodium silicate solids in the form of an aqueous solution is added at a temperature of about 140 F. with stirring followed by the addition of the tripolyphosphate in powder form. The temperature of the crutcher slurry is maintained at 170180 F. for one hour with agitation and there is formed a smooth, pumpable mixture having a total solids content of about 55-60%. It is then pumped into a spray tower where it is spray-dried with air heated to about 600 F. to yield a product in the form of beads.

During the crutching operation where the temperature is maintained at 170180 F., samples were removed at 5, 30 and 60 minute intervals and compared with the final dried product in soil anti-redeposition tests.

It was found that the polyvinyl alcohol was stable during the crutching cycle since the same high level of soil anti-redeposition properties was exhibited by all of 'the samples collected during the crutching operation and by the final dried product. On the other hand, the use of certain grades of polyvinyl alcohol outside the scope of this invention resulted in the products exhibiting substantial decreased soil-suspending effects the longer the composition was aged in the crutcher.

Example II The following dried composition is prepared using the ingredients and procedure of Example 1 except as otherwise described:

Ingredients: Percent Sodium tridecyl benzene sulfonate 17 Coconut monoethanolamide 3 Sodium tripolyphosphate 45 Sodium toluene sulfonate 2.4 Sodium silicate 5.5 Sodium carbonate 2.5 Sodium carboxymethylcellulose 0.3 Polyvinyl alcohol 0.3 Sodium sulfate 18 Moisture 6 The ingredients are mixed in the form of said aqueous slurry in a crutcher for 90 minutes at a temperature between 170" and 180 F. Samples are removed after 5, 30, 60 and 90 minute intervals followed by drum drying of the mixture to obtain a solid product in particulate form. The samples and the dried product are tested in soil i e-deposition tests and exhibited equivalent soil-suspension power of a high level using cotton and resintreated cotton swatches.

Example III A heat-treated composition is prepare as in Example I except that the sodium carboxymethy-lcellulose is omitted from the formulation. The resulting product exhibits no decrease in soil-suspension power after having been aged in the crutcher for minutes at the elevated temperature.

Examples I V-V Other suitable formulations prepared in spray-dried form as described are:

IV, V, Ingredients Per- Percent cent Sodium tridecyl benzene sullonate 35. O 27.0 Sodium tripolyphosphate 3S. 5 47. 0 Sodium silicate 6. O 6.0 Sodium carboxymethylcellulose 0.8 0.8 Polyvinyl alcohol (2.34 cps, 22.3% acetate) 0.1 0.3 Moisture 8. 5 8. 5 Sodium sulfate Bal. Bal.

The above formulations may contain fluorescent dye, corrosion inhibitors and like ingredients in small amounts. The cellulose is a commercial grade such as DuPont 10D.

Many other grades of polyvinyl alcohol having a viscosity within the range of 1.8 to 3 centipoises and 10 to 30% polyvinyl acetate may be employed in similar compositions which exhibit satisfactory soil-suspension effects. Typical examples of such materials are polyvinyl alcohols having a viscosity of 2.34 c.p.s. and an ester content of 2022%, 1.88 c.p.s. and 19.6% ester, 1.98 c.p.s. and 29.4% ester, 2.38 c.p.s. and 12.8% ester, and the like. In addition, other organic detergents may be added or substituted for part of the alkyl aryl sulfonate detergent in the above compositions as desired, examples being sodium lauryl or coconut fatty alcohol sulfate or non-ionic nonyl phenol condensed with an average of about 9.5 moles of ethylene oxide.

Although the present invention has been described with reference to particular embodiments and examples, it will be apparent to those skilled in the art that variations and modifications of this invention can be made and that equivalents can be substituted for various ingredients without departing from the principles and true spirit of the invention.

What is claimed is:

1. A heat-treated solidified detergent composition comprising about 5 to 50% by weight of a water-soluble higher alkyl mono-nuclear aryl sulfonate detergent having about 8 to 15 carbons in said higher alkyl group and in minor proportion to said detergent and sufficient as a soil-suspending agent of water-soluble polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of 10 to 30% by weight, and the balance being primarily water-soluble inorganic builder salts.

2. A heaLtreated solidified detergent composition comprising about 5 to 50% by weight of alkali metal higher alkyl benzene sulfonate detergent having about 8 to 15 carbons in said alkyl group, about 0.1 to 2% by weight of water-soluble polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of 10 to 30% by weight as a soil-suspending agent, and the balance being primarily water-soluble inorganic builder salts.

3. A heat-treated composition comprising about 5 to 50% by weight of water-soluble higher alkyl benzene sulfonate detergent having about 8 to '15 carbon atoms in the alkyl group, about 0.05 to 5% each by weight of (a) an alkali metal salt of carboxy lower alkyl cellulose having up to 3 carbon atoms in the alkyl group, and (b) Water-soluble polyvinyl alcohol having a viscosity of 1.8

to 3 centipoises and a polyvinyl acetate content of 10 to 30% by weight, the balance being primarily water-soluble inorganic builder salts with about 10 to 80% by weight of alkaline inorganic alkali metal builder salts.

4. A spray-dried detergent composition in particulate form comprising about to 50% of alkali metal higher alkyl benzene sulfonate detergent having an average of about 12 to 15 carbons in said alkyl group, about 0.05 to 5% each by weight of a mixture of alkali metal carboxymethylcellulose and water-soluble polyvinyl alcohol soil-suspending agent having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of to 30% by weight, and the balance being primarily water-soluble inorganic alkali metal builder salts with about 10 to 80% by weight of alkali metal polyphosphate.

5. A spray-dried detergent composition in particulate form comprising about 5 to 50% of sodium higher alkyl benzene sulfonate detergent having an average of about 12 to carbons in said alkyl group, about 0.05 to 5% each by weight of a mixture of sodium carboxymethylcellulose and water-soluble polyvinyl alcohol having a viscosity of 1. 8 to 3 centipoises and a polyvinyl acetate content of 10 to 30% by weight, and the balance being primarily water-soluble inorganic builder salts with about 10% to 80% by weight of alkali metal alkaline inorganic builder salts.

6. A process for preparing a heat-treated detergent composition in solid form which comprises forming an aqueous mixture of about to 90% total solids of a water-soluble higher alkyl mono-nuclear aryl sulfonate detergent having about 8 to 15 carbons in said alkyl group in about 5 to 50% by weight of solids, the balance being primarily water-soluble inorganic builder salts and in minor proportion to said detergent and suflicient as a soil-suspending agent of water-soluble polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of 10 to by weight, heating said aqueous mixture at a temperature from about 100 to 200 F., drying said mixture to a solid form, and recovering a heat-treated detergent composition in solid form.

7. A process for preparing a heat-treated and dried detergent composition which comprises forming an aqueous slurry of about 5 to by weight of solids of an alkali metal higher alkyl benzene sulfonate detergent having about 8 to 15 carbons in said alkyl group and 0.05 to 5% by weight of solids of water-soluble polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of 10 to 30% by weight, the balance of total solids being primarily water-soluble inorganic builder salts, the solids content of said aqueous slurry being from the range of about 20% to 90% by weight, heating said slurry at a temperature from about 120 to 180 F. and forming a substantially homogeneous mixture, heat-drying said mixture and recovering a heat-treated and dried detergent composition.

8. A process for manufacturing a spray-dried detergent composition in particulate form which comprises forming an aqueous slurry of about 20 to 90% total solids containing an alkali metal higher alkyl benzene sulfonate detergent having an average of about 12 to 15 carbons in the alkyl group, alkali metal carboxymethylcellulose and water-soluble polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of 10 to 30% by weight, the proportions of a solids basis being about 5 to 50% by weight of said detergent, and 0.05 to 5% each by weight of the cellulose compound and polyvinyl alcohol, the balance of solids being primarily watersoluble inorganic builder salts with about 10 to by weight of alkaline inorganic salts selected from the group consisting of alkali metal polyphosphates and alkali metal silicates, maintaining said mixture at a temperature from about to 200 F. with agitation and forming a substantially homogeneous mixture, spray-drying said mixture at a temperature above about 212 F., and recovering a spray-dried detergent composition in particulate form.

9. A process for manufacturing a spray-dried detergent composition in particulate form which comprises forming an aqueous slurry containing a sodium higher alkyl benzene sulfonate detergent having an average of about 12 to 15 carbons in the alkyl groups, sodium polyphosphate salt, sodium carboxymethylcellulose and water-soluble polyvinyl alcohol having a viscosity of 1.8 to 3 centipoises and a polyvinyl acetate content of 10 to 30% by weight, the proportions of said ingredients on a solids basis being about 5 to 50% by weight of said detergent, 10 to 80% by weight of said polyphosphate and 0.05 to 5% each by weight of the carboxymethylcellulose and polyvinyl alcohol, the solids content of said aqueous slurry being from the range of about 40% to 65% by weight, heating said mixture at a temperature from about to F. and forming a substantially homogeneous aqueous mixture, and spray-drying said mixture at a temperature above about 212 F., and recovering a spray-dried detergent composition in particulate form.

10. A spray dried detergent composition consisting essentially of about 30 weight percent of a water soluble higher alkyl benzene sulfonate detergent, about 0:1 weight percent of a mixture of about equal parts of sodium carboxymethyl cellulose and a polyvinyl alcohol having a viscosity of about 2, and the balance sodium tripolyphosphate.

References Cited by the Examiner UNITED STATES PATENTS 2,755,252 7/1956 Pong et a1 25289 XR 2,798,047 7/ 1957 Touey et al 252-l52 2,870,093 1/1959 Ruff 252-138 XR 2,877,187 3/1959 Henderson et al. 252-137 XR 2,897,155 7/1959' McNaught et al. 252138 XR OTHER REFERENCES Textile Research Journal, vol. 23, No. 11, pages 769-775 (November 1953).

JULIUS GREENWALD, Primary Examiner, 

1. A HEAT-TREATED SOLIDIFIED DETERGENT COMPOSITION COMPRISING ABOUT 5 TO 50% BY WEIGHT OF A WATER-SOLUBLE HIGHER ALKYL MONO-NUCLEAR ARYL SULFONATE DETERGENT HAVING ABOUT 8 TO 15 CARBON IN SAID HIGHER ALKYL GROUP AND IN MINOR PROPORTION TO SAID DETERGENT AND SUFFICIENT AS A SOIL-SUSPENDING AGENT OF WATER-SOLUBLE POLYVINYL ALCOHOL HAVING A VISCOSITY OF 1.8 TO 3 CENTIPOISES AND A POLYVINYL ACETATE CONTENT OF 10 TO 30% BY WEIGHT, AND THE BALANCE BEING-PRIMARILY WATER-SOLUBLE INORGANIC BUILDER SALTS.
 3. A HEAT-TREATED COMPOSITION COMPRISING ABOUT 5 TO 50% BY WEIGHT OF WATER-SOLUBLE HIGHER ALKYL BENZENE SULFONATE DETERGENT HAVING ABOUT 8 TO 15 CARBON ATOMS IN THE ALKYL GROUP, ABOUT 0.05 TO 5% EACH BY WEIGHT OF (A) AN ALKALI METAL SALT OF CARBOXY LOWER ALKYL CELLULOSE HAVING UP TO 3 CARBON ATOMS IN THE ALKYL GROUP, AND (B) WATER-SOLUBLE POLYVINYL ALCOHOL HAVING A VISCOSITY OF 1.8 TO 3 CENTIPOISES AND A POLYVINYL ACETATE CONTENT OF 10 TO 30% BY WEIGHT, THE BALANCE BEING PRIMARILY WATER-SOLUBLE INORGANIC BUILDER SALTS WITH ABOUT 10 TO 80% BY WEIGHT OF ALKALINE INORGANIC ALKALI METAL BUILDER SALTS. 